Filesystem in Userspace (FUSE) is a simple interface for user programs to export a virtual filesystem to Cygwin. It also aims to provide a secure method for non-privileged users to create and mount their own filesystem implementations.
cygfuse supplies an emulation of Linux libfuse/libfuse3. It allows FUSE clients such as sshfs, memfs, ftpfs, etc to make use of certain FUSE providers implemented for Windows.
cygfuse was originally a Cygwin add-on to WinFSP provided by the author of WinFSP, Bill Zissimopoulos. It is still available in that form from source/v1_historical or any WinFSP release. A standard Cygwin package of cygfuse is available via Cygwin's setup.exe. See https://cygwin.com for general setup details.
At this time WinFSP is the only Windows FUSE provider supported. Information about WinFSP can be found at http://www.secfs.net/winfsp.
GPLv3. See the file License.txt.
[Details to be supplied.] In the meantime, see the file source/v1_historical/README.md which is dated but has the essentials.